electricity for use at a later time when a charging source
(sun, wind, water or generator) is not available. They also
provide a reserve of available energy to run loads that require
more power than that provided by the charging source.
Batteries are also one of the most misunderstood components
of alternative energy system. I will attempt to dispel a
"Deep Cycle" is a term used far
to often in the wrong situation. Batteries that are sold
as marine/RV deep cycle - in the 24 and 27 series are no
more than slightly modified starting batteries with a different
label. We speak to clients on a daily basis who purchase
these batteries at a discount retailer, or have been told
these are the proper batteries for the application, only
to find out a year later they battery requires replacement.
These batteries, as well as any car type starting batteries,
including 4D and 8D starting batteries are simply not suitable
for alternative energy applications and will yield unsatisfactory
A true deep cycle battery, such as a golf cart of forklift
batteries are designed from the ground up for deep cycling
applications. This does not mean, however, you should completely
discharge the batteries on a regular basis! Any battery which
is rated in cold cranking amps is not a deep cycle.
Cycling - The deeper you discharge a lead-acid
battery, the shorter it's lifespan. Period. Small batteries
(NiCad) for consumer goods and electronics have completely
different charging characteristics, and actually require
full discharges to maintain their capacity. A battery bank
should be sized for no more than a 50% discharge on a regular
basis. If it gets discharged deeper than that occasionally,
that's life, but you should not always discharge your batteries
until they will no longer operate.
Used batteries - There are many people
who report getting "great deals" on old phone company
batteries, or standby UPS batteries. There are risks associated
with purchase of any used gear. If you are able to do proper
load testing on a bank of batteries you are purchasing, it
will tell you exactly what condition they are in. Relying
simply on their age or the reported usage will not tell you
the condition they are really in. Be cautious! You could
end up with 2000 lbs of batteries that are no good and then
you must often pay to have them disposed of properly.
information on batteries
University. All the information you ever want to
know about batteries.